High durability sulfonated poly (ether ether ketone)-ceria nanocomposite membranes for proton exchange membrane fuel cell applications

Abstract

Nanocomposite fuel cell membranes based on sulfonated poly (ether ether ketone) (SPEEK) incorporating ceria nanoparticles were investigated for fuel cell performance and durability. The ceria nanoparticles were synthesized using the microwave-induced gel combustion method and characterized by XRD and FESEM. Pure SPEEK and SPEEK-CeO2 nanocomposite membranes were prepared by solution casting. The physicochemical properties of the prepared membranes were studied using XRD, FESEM, TGA, water uptake, and tensile tests. The morphological investigations revealed a uniform structure for the prepared membranes. The thermal and mechanical analyses confirmed that the nanocomposite membrane had improved properties over the pure SPEEK membrane. Fuel cell performance measurements showed similar polarization data for the nanocomposite and pure SPEEK membranes. However, the durability of the nanocomposite membrane under accelerated stress test (AST) conditions was significantly enhanced compared to the pure SPEEK membrane. In addition, the nanocomposite membrane exhibited lower hydrogen crossover and better proton conductivity than pure SPEEK after ASTs. FESEM results with fresh and used membrane electrode assemblies showed that the nanocomposite membrane was more stable. The results indicate that SPEEK-CeO2 nanocomposite membranes are potentially good candidates for proton exchange membrane fuel cells.